Edwin h



H.111; BENNETT. Tub e 'I a; s ten'i n g's.

Patented Dec. 14, 188 0.

N-PETERS, F lOTO-UTNDGRAPHER, WASHINGTON, u c

UN TED STATES PATENT OFFICEO EDWIN H. BENNETT,.OF BAYONNE, N W JERsEY,ASSIGNOR To eEoReE H. BABOOOK AND sTEPHEN wrncox, OF NEW YORK, N. Y.

TUBE-FASTENING.

SPECIFICATION forming part of Letters Batent No. 235,406, dated'December14, 1880.

Application filed October 29, 1879.

. To all whom it may concern:

Be it known that I, EDWIN H. BENNETT, of Bayonne, Hudson county, andState of New Jersey, have invented certain new and useful I 5Improvements relating to Tube -Fastenings; and I do hereby declare thatthe following is a full and exact description thereof.

The invention is adapted for securing the tubes of steam-boilers andanalogous struct- 1o ures requiring a tight fastening, adapted to endurehigh temperatures and great strains. It is intended more particularlyfor the style,

of boilers set forth in the several patents to Babcock and Wilcox,having the water inclosed 1 5 in tubes, and small end chambers ofcast-iron pered, so that the outer end is the largest. I, employ anexpanding-tool, adapted to give the same taper to the tube end and forcethe metal of the tube into the corresponding conical form, applying onlysufficient force to slightly imprint the casting into the outer surfaceof the expanded tube.

The strain on the connection is always forc- 3 ing the tapered surfacesinto a closer connec- A tight joint results with little distor I tion.

lion of the metal of the tube.

My invention allows tubes to serve successfully which possess a lessdegree of ductility than .is required for the ordinary modes of setting.

The accompanying drawings form a part of I this specification, andrepresent what Iconsider the best means of carrying out the in- 4 5vention.

Figure 1 is a central longitudinal section through one of the tube endsand the adjacent parts in the act of being expanded. Fig. 2 is ancndview of the same'with a cross-section through the body of the tube.Fig. 3 is an elevation, partly in section, showing a number of theconnections on a smaller scale.

Similar letters of reference indicate like parts in all the figures.

7 A is the body of the tube, and A a conical g5 end formed thereon. B isthe main body of i an end casting, and b the tapering hole formedtherein to receive the tube.

M M, &c., are the rollers of the expander. They are caged in a ring, N,and are forced 6 apart by a tapering mandrel, P,which is turn ed by acrank or otherwise, and is forced axially, as required, to present alarger diameter within the rollers, and thus to force the rollers Moutward and effect the expansion. 6

The hole bin the casting maybe finished with a tool, to give a moreexactly mathematical form; but I do not consider such necessary. Iesteem it an important advantage of the invention that the holes may beproduced with perfection by the ordinary process of casting, and requireno tooling. Q

The rollers M may be tapered in the same direction and to the samedegree as the mandrel. In other words, the proper degree of taper forthe hole being determined, it may be divided between the mandrel and therollers. This allows the rollers and mandrel to roll together with nosliding and with mathematical precision; but Ido not esteem this featureessential to success. The rollers may be made absolutely cylindrical ortapered in the opposite direction, the mandrel being suitably taperedwith each to induce the required degree of taper in the interior, andconsequently 0t 8 the exterior of the tube ends A.

I prefer to expand the tubes only to such extent as to slightly imprintthe casting B into the outer tapering surface of the tube end A. Thebearing-surface is made narrow to 0 facilitate such imprinting.

